Digital BW, The Print

I'm interested in BO printing for esthetical reasons (Tri-X grain
Rodinal 1/25> document paper prints etc in the past) but do not
have the right printers in house. I've no experience other than
having seen some prints with Epson dye with a 1280 and I wasn't
impressed, the greyscale is alright but the consistency isn't,
banding being the main problem. My 9000's here (Generations black
or Ultratone black) are better in consistency + linearity
(Wasatch SoftRip) but the droplets are too big.

I've written it before that I think there's a way to improve BO
printing by using more nozzles than the nozzles of the black head
only. If the quantity of black ink per head is reduced by the
number of heads used there must be a gain in consistency and
quality. A driver that allows linearisation per head on top of
that should improve the consistency even more. There still is a
need for a printer with small droplets and that's where I miss
some information.

A 4 colour printer should be adequate. The new R800 (7  heads,
not yet available) has the finest droplet size so far but which
existing 4 colour printer comes next ? How is the droplet size
distribution, 2>3 sizes per resolution setting? How many nozzles
per colour ? What would be the best candidate ? A3/A4 size.

Suppose one can use three heads at 1/3 of their normal ink
quantity and get the smallest droplet size (of 3 sizes) for the
three heads when printing 100% black. If there's one that has 4
droplet sizes take 4 heads. Next choice is the amount of nozzles
per colour, the more the better.

Would that give an improvement over  a single head BO print with
the same printer ?
There's no gain in smaller droplets at the highlights. There
should be a gain in smaller droplets used from 33% up to 100% if
that is actually working out as nice in practice as in theory.
Bleeding could spoil the fun though the ink amount is the same
and it takes more time to lay down 100% from 3 heads with finer
droplets than from one with bigger droplets = more drying time.
The same amount of ink in smaller droplets has however more total
circumference length which should increase bleed effect. That can
be compensated with linearising but small changes in humidity and
papercoatings could show faster in multihead BO printing than in
singlehead BO printing. If linearisation is an easy task it
should be done daily.

3 times the nozzle amount must add to the consistency, especially
on banding, the chance that a nozzle doesn't work gets 3x higher
with the number of nozzles but its effect will be reduced with
2/3 as well. The same for nozzle deflection. A total blocking of
one nozzle is just one state of quality decrease and its one that
is easily noticed. Much more frequent is a permanent difference
between the outputs of nozzles. That is much better compensated
in multihead BO printing than it is in singlehead BO printing.
There should be a smoother tonal gradation with multihead BO
printing from 33% to the shadows and an overall better
consistency which should in itself improve the smoothness of the
highlights too.

There's one thing that may spoil the whole concept. Are the
dithering, weaving routines in Black Only printing the same or
similar to the CMYK routines ?
In QTR or another driver?
QTR has an advantage as not that many RIPs will drive the desktop
models with their finer droplets and QTR has good routines for
dithering etc. The Wasatch SoftRip that I have could do all but
lacks in desktop printer drivers and its d/w routines are not
that good. Taking out one of the CMY channels could address the
interference of black generation in some drivers and RIPs. I
still have PressReady that I used for a 3000 and wonder whether
that RIP could be used by feeding it odd CMYK files.

Are there pitfalls that I missed ?

Ernst